Report No. 4 -- The Russian approach to reactor pressure vessel integrity

This report is divided into two parts. Part one discusses the main principles of calculation of reactor vessel brittle fracture resistance. Calculations are performed for all operating conditions, including normal operating conditions, operational occurrences, accident conditions, and hydraulic tests. Part two discussed the analysis of the measures to ensure brittle fracture resistance of WWER-440 pressure vessels under conditions of thermal shock. Analysis of the characteristics of pressure vessel materials with regard for effect of neutron irradiation is presented.